Ceiling structure

ABSTRACT

A fire-resistant ceiling structure which is insulative to heat and sound, comprises a supporting structure with a ceiling suspended therefrom and made of boards of mineral wool, wool glass or the like. The ceiling is formed by attaching the boards to each other at their edges with a bonding agent, and in the joints between the boards are embedded supporting members for suspending the ceiling from the supporting structure.

United States Patent Hirvensalo May 27, 197 5 CEILING STRUCTURE [56] References Cited [75] Inventor: Erkki Olli Yrjana Hirvensalo, UNITED STATES PATENTS Helsinki, Finland 2,128,308 8/1938 Lord 52/434 [73] Assignee: Kaarina Hirvensalo, Helsinki, FOREIGN PATENTS 0 APPLICATIONS Finland 70,415 5/1959 France 52/441 [22] Flled: 1974 Primary Examiner-John E. Murtagh [21] Appl. No.: 454,014 Attorney, Agent, or Firm-Waters, Schwartz & Nissen Related US. Application Data ABSTRACT [63] fgg zggfgigg ir 5, 3 ggfi gf ii rgg ggg A fire-resistant ceiling structure which is insulative to Sen f 32 034 April 27 1970 abandoned heat and sound, comprises a supporting structure with Y a ceiling suspended therefrom and made of boards of [30] Foreign Application Priority Data mineral W001, W001 glass or the like. The ceiling is A 25 1969 1 d 1220/69 formed by attaching the boards to each other at their 1970 i 1055/70 edges with a bonding agent, and in the joints between m an the boards are embedded supporting members for sus- U S Cl 52/434 52/22 52/442, pending the ceiling from the supporting structure.

52/484 [5]] Int. Cl E04b 5/52 [58] Field of Search 52/484, 594, 418, 438, 19 Claims, 10 Drawing Figures c\ LO OQJ CEILING STRUCTURE CROSS-RELATED APPLICATION This application is a C-I'P of my earlier copending application Ser. No. 257,812 filed May 30, 1972, now abandoned which in turn is a C-I-P of Ser. No. 32,034 filed Apr. 27, 1970, and now abandoned.

BACKGROUND OF THE INVENTION a. Field of the Invention The invention relates to insulating ceiling construction with fibrous, mineral wool boards or blocks.

b. Prior Art Suspending ceilings are known which are made of fibrous boards or blocks which rest on a grid of inverted metal T members and angle members, which rest on external supports. In order to provide intermediate support for the ceiling, the grid members are connected by suspension members to the overhead joists. There is no attachment between adjacent boards and each board can be individually removed from the grid to provide access above the ceiling.

It is also known to construct a flooring consisting of longitudinal and transverse iron joists with a filling of bricks between them. The bricks are provided with recesses which receive the flanges of the joists and the space between the bricks at each of the joints is filled with a binding agent.

In the first of the above constructions, each block is supported along all four edges thereof, whereas in the second construction, the bricks are supported along two parallel edges. The supports are incumbent for maintaining the structural integrity of the ceiling. In the first construction, there is no attachment between adjacent blocks, and in the second construction there is merely a shear connection between the bricks with little or no capability of transmitting bending moments, it being necessary to provide external support for the bricks by the iron joists to prevent collapse of the structure.

The presence of the metal supports adversely affect the fire-resistant capability of the structure. Thus, even though the blocks or bricks can be made fireproof, the metal supports are exposed at the undersurface of the ceiling and a fire beneath the ceiling can cause deformation of the metal supports and collapse of the blocks or bricks to expose the joists thereabove to the fire.

Furthermore, because the known structure is not continuous" at the joints (cannot transmit bending moment) it becomes necessary to provide a support member at each joint which is externally supported. This is costly and is tedious in construction.

SUMMARY OF THE INVENTION An object of the invention is to avoid the disadvantages associated with known ceiling construction.

Another object of the invention is to provide a novel ceiling construction which has substantial fire resistance.

The assembly of the ceiling is particularly simple in practice and the ceiling can be supported at random from the overhead joists.

According to the invention, a heat and soundinsulating ceiling structure is suspended from an over head supporting structure and comprises a slab constituted of mineral wool boards which are heat and sound insulating and composed of fibrous material which is heat-resistant and fiameproof, and means forming joints binding the boards to each other at their edges, said means consisting essentially of a heat-resistant bonding agent extending substantially from the upper to the lower surface of adjacent boards, the bonding agent penetrating into the boards at said edges to rigidify the same and provide bending continuity of the slab of the joint, and supporting means embedded in said bonding agent. The slab is suspended from the overhead supporting structure solely through the intermediary of said supporting means, the latter comprising supporting strips having upper margins which extend above the slab, and lower margins extending into the respective joints to a distance above the lower surface of the board, the lower margins of said strips being covered by said bonding agent and only the bonding agent in said joints being exposed at the lower surfaces of the boards.

The supporting means may be in the form of strips which are perforated where they are embedded in the joints in order to minimize heat transfer to the overhead supporting structure by conduction and to maximize the adherence of the strips in the joints. The strips can be continuous along the length of the boards, or they can be interrupted since the slab does not rely on the strips for its strength. The support strips can be connected to the overhead structure at random locations to provide the necessary support for the slab, it being worthy of note that the slab can be supported only from above. This is due to the fact that the slab is continuous at the joints and forms a unit having structural integrity throughout as a rigid construction.

As an alternative, the supporting means can be in the form ofa wire embedded in the adhesive bonding agent at each joint and locally deformed to extend above the slab for being suspended from the overhead structure.

According to a further embodiment, the support means may be constituted as spaced elements in the form of plates or wire members which are embedded in the joints and individually project above the slab for suspension from the overhead structure.

A method of suspending a ceiling from an overhead support structure comprises securing boards or blocks of fibrous material together to form a continuous slab by bonding the blocks together at their edges with a heat resistant adhesive to form joints with bending from the overhead support structure, and embedding the supporting elements partway into the depth of respective joints before the adhesive thereof has hardened. The slab is not rigid until the adhesive is dry. There is no suspension before that. The underface of the slab is constituted by the lower faces of the blocks and the lower surfaces of the adhesive at the joints, the supporting elements being efficiently concealed in the joints.

According to one embodiment, the blocks are directly supported from the suspended supporting elements and the adhesive is then applied to the blocks. Thereby, the need for support of the blocks from below is avoided.

In some cases, it may be convenient to use temporary props for the blocks and in such circumstances the adhesive is applied to the faces of the blocks when the blocks are supported by the props. After the adhesive has hardened, the temporary props are removed.

When props are used, the blocks are secured in succession in rows, and the temporary props are separable in rows. Thereby the props removed from one row can be used for supporting a successive row of blocks.

The invention is adapted to the use of slabs in existing structures or for new constructions.

For new constructions, the slab can be assembled with the overhead supporting structure at a level below the final height of the ceiling and then the supporting structure and ceiling can be hoisted as a unit so that the ceiling is at the final desired level.

Since there is no metallic or other heat-conducting element passing all the way through the joints, the ceiling structure according to the invention has good thermal insulating capacity. In the event of fire, a long time is needed before the supporting elements embedded in the ceiling are heated to such a degree that they lose their mechanical strength. A ceiling structure according to the invention is therefore first-resistant for the overhead structure. Its fire-resistivity is insured by using a heat-resistant bonding agent and by taking appropriate care that the boards during hardening, are pressed together and thus remain firmly jointed together. In this manner the ceiling forms a continuous slab having a strength substantially greater than that of a ceiling composed of boards which are loose or which have been loosely connected with each other.

The adherence of the supporting elements in the joints may be improved by perforating the supporting elements. Additionally, at these perforations the thermal conductivity of the supporting elements is considerably less than that of solid strip, and this contributes to higher heat-insulating capacity and fire-resistance of the structure. It is possible, in order to increase the adhesion, to pass hooked pins through the supporting element.

The ceiling can be suspended from an overhead structure of entirely different shape and the ceiling may be horizontal and suspended from a rigid roof and be well insulative with respect to heat, sound, moisture and fire while providing sufficient support strength.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical section taken through a ceiling construction according to the invention;

FIG. 2 shows a ceiling and roof structure according to the invention;

FIG. 3 is a vertical section through the ceiling showing its manner of assembly;

FIG. 4 is a perspective view of a portion of a strip member of the ceiling construction;

FIGS. 4a and 4b are perspective views of other embodiments of strip members of the ceiling construction.

FIG. 5 is a vertical section through the ceiling showing a modified form of support element;

FIG. 6 is a vertical section through the ceiling showing another modified form of support element;

FIG. 6a is a perspective view of the support element of FIG. 6; and

FIG. 7 is a vertical section through the ceiling showing another modified form of support element.

DETAILED DESCRIPTION vided at the location where two layers 2 overlap as shown at the right in FIG. 1. Each member 3 is threaded at its upper end and provided with nuts 4 and 5 for securing and pressing the overlapped sheets of layer 2 together. Where the member 3 does not serve to connect two sheets together, only nut 4 is needed to suspend member 3. The lower end of the member 3 has a hook shape portion and it supports a strip 6, which is embedded in a joint 9 between adjacent insulating boards or blocks 7. The blocks are made of mineral wool or glass wool. The joint 9 is formed by a bonding agent which is resistant to heat anad moisture and the bonding agent unites the boards 7 with each other and with the supporting strip 6. As seen in FIG. 4, the strip 6 is provided with perforations 8 at its lower end to prevent heat transmission from the space below the ceiling to the space thereabove and to the overhead joists. The strips 6 should not extend into the joint beyond onehalf the thickness of the boards. The lower surfaces of the insulating boards may be painted a desired color or coated in any other way. The strips also can be in net form, as shown at 6a in FIG. 4a, or the strip can be perforated by expanding, as shown at 6b in FIG. 4b.

A ceiling structure according to this embodiment of the invention is particularly heat and sound-insulating and resistant to fire at its undersurface.

The blocks are well known and composed of fibrous material which is heat and sound insulative. The individual blocks are relatively flexible and compressible when pressed at their upper and lower surfaces. By way of example, the blocks may be made of mineral wool and the size of the blocks can be 10 cm X 88 cm X 170 cm with a specific weight of 75 kg/m. The bonding agent is an adhesive which penetrates into the spaces between the fibers of adjacent blocks and when it hardens its rigidfies the blocks at their edges so that they are no longer compressible thereat. Furthermore, the adhesive bonds the fibers of the adjoining blocks together so that a rigid slab is formed by the joined blocks. A suitable adhesive is one formed by mixing finely divided S,-O with waterglass in a mixture ratio of 60-70 percent S 0 and 30-40 percent waterglass. A particular embodiment is as follows:

Na O 10.98% by weight 8.0 28.53% by weight H O 60.49% by weight The $.0 is of a mesh size such that 20% passes through a sieve of mesh size i.e. ISO of a hole size of 0.210 mm. The viscosity of the mixture is about 5000 centipoise. The thickness of the adhesive in its final hardened state is about 4 7 mm. The time in which it takes for the adhesive to harden is about 1 hour at a temperature of 30 C and about 5 hours at a temperature of 5C. The adhesive has also been found to be usable as a mortar for interior bricklaying in heating furnaces.

The joints which are formed at each of the places where the blocks are joined are continuous joints in the structural sense in that the slab can transmit bending moments at the joints. Specifically, the adhesive at the joints so bonds the fibers as to form continuity in the longitudinal direction so that a bending moment of external forces can be resisted by an internal moment as a couple produced by tensile and compressive stresses acting on the fibers of the slab. This is to be contrasted with a simple shear connection as by securing two bricks together with mortar, in which case it is necessary to provide external support at the joint, such as by a beam or the like. By making the slab continuous, the need for external support at the joint is eliminated and it is only necessary to suspend the slab from the overhead joists at any convenient locations. It is of advantage both structurally and in the method of construction to support the slab by the strips 6 at random in the slab. If the strip is continuous throughout the joint. the joint acts as a reinforced continuous concrete beam. In this case distances between suspending points may be great.

The entire character of the individual blocks is changed when they are assembled as the slab, and while each block of itself is flexible and has little strength, the resulting slab has great strength due to the rigidity of the adhesive joints 9 and the bending continuity afforded thereby.

In lieu of strips 6 there may be employed a support element in the form of a Wire 16., which extends throughout the length of the joint and which is provided with a projecting portion 17 which extends above the upper surface of the slab to engage the lower end of suspender member 3, as shown in FIG. 5. The continuous wire 16 acts again as a reinforcement in a concrete beam.

The method of assembly of the ceiling with the supporting elements as shown in FIGS. 4 and 5, is as follows:

Suspender members 3 are attached to the joists 1 at the location of joints 9 and blocks 7 are brought into position and rested on temporary props 20, as shown in FIG. 3. A covering strip 21 of the same material as block 7 is placed at the top surface of blocks so as to contact the undersurface of two adjoining blocks 7. When one row of blocks 7 has been placed on the props, the edges thereof are coated with the adhesive which is to form the joints. The edges of the next row of blocks are then also coated with adhesive and adjacent blocks are pressed together so that the adhesive will permeate the fibrous material and form the necessary joints. The strip members 6 are embedded in the adhesive material and after the material has hardened, will be permanently formed in the joint between adjacent blocks. It is to be understood that when each block, in a row, is put into place, it will adjoin an adjacent block in its own row with its end edge, and an adjacent block in the adjoining row with a side edge. Hence, two joints are formed simultaneously when each block is placed into position. The slab is built in rows in this manner and after the adhesive between two rows has sufficiently hardened, the prop 20 thereof may be removed and employed for connecting subsequent rows as shown in dotted outline in FIG. 3. Herein can be seen the arrangement Where the last row of blocks has the adhesive applied to the side face thereof and a block from the next row is about to be placed on the prop and brought into contact with the adhesive. It is to be noted that the block which is to be brought into contact, also has adhesive on its side edge.

FIGS. 6 and 7 show a modified arrangement in which the need for props is obviated.

Specifically, FIGS. 6 and 7 show support elements which are spaced along the joint 9 and in FIG. 6 the support element is designated by numeral 26, whereas in FIG. 7 the support elements are designated by numeral 36. Each of the support elements is hung from a respective suspender element 3 and as shown in FIG. 6, the support element 26 is associated with four pins 27 which can be forcibly inserted into the adjacent block 7 in order to hold the block while the adhesive is hardening. In this way the entire slab structure is assembled from the above solely through the intermediary of the support elements and the suspender elements 3. In the embodiment of FIGS. 6 and 6a, the support element is formed as a wire and the pins 27 are fixed thereto. In the embodiment of FIG. 7, the plate elements 36 are formed with apertures in which individual pins 37 can be inserted to pierce the adjoining block and thereby support the same from the elements 36. The presence of pins 27 and 37 aids in the embedding of the support elements in the joint. In these cases. where support elements are discontinuous, it is advantageous to mix the joint adhesive with reinforcing fibers, e.g. asbestos, which form the reinforcement in the similar way as continuous strips as stated before, so that the distances between suspending points may be great.

FIG. 2 shows a ceiling-and-roof structure in which the roof is of the common ridge type and the ceiling is horizontal. The supporting structure of the ceilingand roof includes inclined joists 1. The roof surfacing layer (sheathing) is indicated by reference numeral 2' and suspender members 3 carry the slab 11, which is horizontal and composed of boards 7 as in FIG. 1. FIG. 2 also shows a cross bar 10 in the space above the slab. This space is protected against fire. This has been established by tests run by the State Institute of Technical Research of Finland and the results are contained in report No. a 1819/71 the contents of which are incorporated by reference herein.

The supporting strip 6 may be itself rigid to such an extent, or so reinforced, that it may be carried and supported exclusively by the supporting structure of the ceiling and roof, whereby the slab imposes no load whatsoever on the layer 2. Also, the supporting strip 6 may be perforated in its entirety. The lower surface of the slab may be painted or covered.

This covering may be accomplished in various ways, such as with thin foils of with plates of greater thick- 'ness. The plates may be positioned either to cover the joints such as by strips 21, which further contribute to the, otherwise good, fireresistance of the ceiling structure, or the covering may cover the slab in its entirety, whereby additionally an attractive appearance of the ceiling is achieved. In both instances when a covering is used, the lower margin of the strip 6 may be embedded to a greater depth in this so-called composite structure without detriment to its thermal and fire insulating capacity.

The painting of the lower surface of the slab may be effected by spraying onto the lower surface a mass which increases the rigidity of this surface and adds to the strength of the entire structure and/or improves the fire and thermal insulating properties and/or improves its appearance. For such spraying, inorganic or organic spraying media or combinations thereof may be used. The fibrous constituents of the boards act as reinforcements for the sprayed substance, whereby the surface of the insulating board becomes especially firm and strong.

The coating may, in both instances, also be chosen so that it forms a good fire-insulating layer, which need not absolutely possess particularly great strength, such as vermiculite.

The blocks may be made of rock wool or fiber glass and may possess mechanical strength. Thereby, the slab may be made to have such great strength that it is possible to walk on it. The thickness of the coating may vary within wide limits, from a thin foil up to plates or coatings applied by spraying which have a thickness equal to that of the slab, or even greater.

When the ceiling construction is to be used in existing structures, the slab is erected in place by means of the suspender members 3 which are directly attached to the overhead joists. In the case of new constructions however, it may be advantageous to assemble the roof and ceiling at a convenient low working level below the final height of the ceiling and after the entire structure has been assembled, the roof and ceiling is hoisted as a unit until the ceiling is at the final desired level.

What is claimed is:

1. A heat and sound-insulating ceiling structure suspended from a supporting structure, comprising a slab constituted of mineral wool boards which are heat and sound insulative and composed of fibrous material which is heat-resistant and flameproof, and means forming joints binding the boards to each other at their edges, said means consisting essentially of a heatresistant bonding agent extending substantially from the upper to the lower surfaces of adjacent boards, the bonding agent penetrating into the boards at said edges to rigidify the same and provide bending continuity of the slab at the joint, and supporting means embedded in said bonding agent, said slab being suspended from the supporting structure solely through the intermediary of said supporting means, said supporting means having upper margins which extend above the slab, and lower margins extending into the respective joints to a distance above the lower surface of the boards, said lower margins of said supporting means being covered by said bonding agent, only the bonding agent in said joints being exposed at the lower surfaces of the boards.

2. A ceiling structure according to claim 1 wherein the supporting means comprises strips which are perforated at their lower margins.

3. A ceiling structure according to claim 1 comprising a surfacing layer on said supporting structure, said surfacing layer including a plurality of overlapped sheets, the supporting means being fixed to the surfacing layer where adjacent sheets of the surfacing layer overlap, such that the slab serves to attach the sheets of the surfacing layer together.

4. A ceiling structure according to claim 1 wherein the bonding agent binding the boards together is resistant to moisture and acids.

5. A ceiling structure according to claim 1 comprising a surface coating on the lower surface of the insulating boards covering the boards and joints.

6. A ceiling structure according to claim 5 wherein said coating is a plate attached to the slab.

7. A ceiling structure according to claim 5 wherein said coating is a spray layer.

8. A ceiling structure as claimed in claim 1 comprising strips of fibrous material which are heat-resistant and flameproof bonded to the slab to extend along and cover said joints.

9. A ceiling structure as claimed in claim 8 wherein said strips are bonded to the slab by means of said heatresistant bonding agent.

10. A ceiling structure as claimed in claim 1 wherein said edges of the boards are flat, continuous surfaces.

11. A ceiling structure as claimed in claim 10 wherein the edges of adjacent boards are parallel to one another.

12. A ceiling structure as claimed in claim 1 wherein said supporting means is perforate where it is embedded in said bonding agent.

13. A ceiling structure as claimed in claim 1 wherein said supporting means extends to a depth in the bonding agent not more than one-half the thickness of the boards.

14. A ceiling structure as claimed in claim 1 wherein said supporting means comprises a wire embedded in said joint and including locally deformed portions extending above the slab and constituting said upper margins.

15. A ceiling structure as claimed in claim 1 wherein said supporting means comprises spaced elements embedded in the joints and including respective individual portions extending above the slab and constituting said upper margins.

16. A ceiling structure as claimed in claim 15 wherein said spaced elements are plates.

17. A ceiling structure as claimed in claim 15 wherein said spaced elements are wires bent to triangular form.

18. A ceiling structure as claimed in claim 1 wherein said supporting means comprises strips of net construction.

19. A ceiling structure as claimed in claim 1 wherein said supporting means comprises strips whose upper margins are constituted as solid plates and whose lower margins are of expanded lattice-like construction. 

1. A heat and sound-insulating ceiling structure suspended from a supporting structure, comprising a slab constituted of mineral wool boards which are heat and sound insulative and composed of fibrous material which is heat-resistant and flameproof, and means forming joints binding the boards to each other at their edges, said means consisting essentially of a heatresistant bonding agent extending substantially from the upper to the lower surfaces of adjacent boards, the bonding agent penetrating into the boards at said edges to rigidify the same and provide bending continuity of the slab at the joint, and supporting means embedded in said bonding agent, said slab being suspended from the supporting structure solely through the intermediary of said supporting means, said supporting means having upper margins which extend above the slab, and lower margins extending into the respective joints to a distance above the lower surface of the boards, said lower margins of said supporting means being covered by said bonding agent, only the bonding agent in said joints being exposed at the lower surfaces of the boards.
 2. A ceiling structure according to claim 1 wherein the supporting means comprises strips which are perforated at their lower margins.
 3. A ceiling structure according to claim 1 comprising a surfacing layer on said supporting structure, said surfacing layer including a plurality of overlapped sheets, the supporting means being fixed to the surfacing layer where adjacent sheets of the surfacing layer overlap, such that the slab serves to attach the sheets of the surfacing layer together.
 4. A ceiling structure according to claim 1 wherein the bonding agent binding the bOards together is resistant to moisture and acids.
 5. A ceiling structure according to claim 1 comprising a surface coating on the lower surface of the insulating boards covering the boards and joints.
 6. A ceiling structure according to claim 5 wherein said coating is a plate attached to the slab.
 7. A ceiling structure according to claim 5 wherein said coating is a spray layer.
 8. A ceiling structure as claimed in claim 1 comprising strips of fibrous material which are heat-resistant and flameproof bonded to the slab to extend along and cover said joints.
 9. A ceiling structure as claimed in claim 8 wherein said strips are bonded to the slab by means of said heat-resistant bonding agent.
 10. A ceiling structure as claimed in claim 1 wherein said edges of the boards are flat, continuous surfaces.
 11. A ceiling structure as claimed in claim 10 wherein the edges of adjacent boards are parallel to one another.
 12. A ceiling structure as claimed in claim 1 wherein said supporting means is perforate where it is embedded in said bonding agent.
 13. A ceiling structure as claimed in claim 1 wherein said supporting means extends to a depth in the bonding agent not more than one-half the thickness of the boards.
 14. A ceiling structure as claimed in claim 1 wherein said supporting means comprises a wire embedded in said joint and including locally deformed portions extending above the slab and constituting said upper margins.
 15. A ceiling structure as claimed in claim 1 wherein said supporting means comprises spaced elements embedded in the joints and including respective individual portions extending above the slab and constituting said upper margins.
 16. A ceiling structure as claimed in claim 15 wherein said spaced elements are plates.
 17. A ceiling structure as claimed in claim 15 wherein said spaced elements are wires bent to triangular form.
 18. A ceiling structure as claimed in claim 1 wherein said supporting means comprises strips of net construction.
 19. A ceiling structure as claimed in claim 1 wherein said supporting means comprises strips whose upper margins are constituted as solid plates and whose lower margins are of expanded lattice-like construction. 